Method for correcting the anisochronism of a timepiece, and the timepiece obtained by the application of this method



Aprll 3, 1962 A. BEYNER 3,028,511

METHOD FOR CORRECTING THE A OCHRONISM OF A TIMEPIECE, AND THE TIMEPIOBTAINED BY THE APPLICATION OF wars METHOD Filed May 15, 1959 mum/70g Ngi ATTORNEY nitd States The present invention relates to a method of atleast partially correcting the anisochronism of the electromagneticallymaintained oscillating regulator member of a timepiece of the typeforming the subject of Patent No. 2,946,940, Beyner et al., issued July26, 1960, that is to say, a timepiece in which the regulator member isrigid with a magnet oscillating in the neighbourhood of a ring andproducing by induction, in a pick-up winding, an im pulse signalcontrolling the feed of a driving winding, at

the rate of one driving impulse per oscillation of the bal- I ancewheel.

The invention also concerns the timepiece obtained by the application ofthis method.

The regulator member of a timepiece, whether it be electromagneticallyor mechanically maintained, always has residual anisochronism,regardless of the measures applied to render it isochronous. entinvention is further to reduce this residual anisochronism, or even toeliminate it, by creating by means of an action on the device by whichthe regulator is maintained,

a directed cause of-anisochronism such as tocornpensate at leastpartially for the aforesaid residual anisochromsm.

The method according to the invention is characterised by the fact thatthe cause of directed anisochronism is created by disposing the ring andthe oscillating magnet slightly eccen-trically in relation to oneanother.

The timepiece according to the present inventionis characterised by thefact that the ring and the oscillating magnet are disposed slightlyeccentrically in relation to one another.

The accompanying drawings, in which only the parts necessary {or anunderstanding of the invention are shown, illustrate by way of exampletwo constructional forms of the subject of the invention.

FIGURE 1 is a plan view of a detail of a first constructional form of atimepiece, and

FIGURE 2 is a plan View of a detail of a second constructional form of atimepiece.

In the first constructional form, the balance wheel of the timepiececonsists of a magnetised bar 1 oscillating within a ring 2, in the planeof the latter. The magnet is subjected to the action of a regulatinghair spring (not shown). The ring 2 has two lugs 2a, through which thereextend fixing screws 3 engaging in the plate 4 of the movement frame.The ring is intended to divide the magnetic flux of the magnet 1 intotwo partial fluxes 5 and 6 The ring 2 supports a pick-up winding 7 anddriving winding 8 of pancake type, situated in the air gap. During thetravel of the north pole of the magnet past the pick-up winding 7, acurrent is induced in this winding and is transmitted through anamplifier circuit (not shown) to the driving winding 8. The operationthereof is described in detail in Patent No. 2,946,940, Beyner et al.

The ring 2 is open at 9, at a point diametrically opposite the pick-upwinding 7. A cam 10 rigid with a slotted control head 11 is pivotallymounted on the frame of the movement, between the two ends 2a and 2b ofthe ring. A spring 12in the form of an open ring, fixed to the movementplate 4 by a screw 13, acts on these The object of the presends of thering so as to maintain them against the cam 10. Owing to thisarrangement, it is possible, by manipulating the control head 11, toopen or close the ring to a variable extent, thus creating between thering and the oscillating magnet an eccentricity by which theoscillations of the magnet are magnetically affected. The anisochronismthus introduced into the oscillating systern, and which is adjustable,can at least partially compensate for the causes of anisochronismpresent in any oscillating regulator (balance wheel-hair spring system)of a timepiece.

Thus, by turning the eccentric 10 in such manner as to reduce the widthof the slot 9', the magnet 1 is moved towards the surfaces of the ringdesignated 14 and 15, whereby the small arcs of the oscillating magnetare advanced. On the other hand, when the width of the slot 9 isincreased, the surfaces 14 and 15 of the ring are moved away from themagnet 1, whereby the small arcs of the magnet are retarded.

The width of the slots in thering may be adjusted by means other thanthe cam 16 described and illustrated. Thus, it is possible to use, forexample, a wedge-shaped spacer member introduced between the'ends of thering and shifted by means of an adjustment screw. 7

The slot 9 in the ring has, in addition, the effect of reducing one ofthe partial magnetic fluxes of the magnet in favour of the other whenthe magnet occupies a position differing from its position ofequilibrium as illustrated in the drawing, whereby the quality of thesignal induced in the pick-up winding 7 is improved (see Patent No.2,946,940, Beyner et al. In order that this effect may be retained, thecam 10 and the spring 12 will consist of a non-magnetic material.

In the constructional form of FIGURE 2 the ring designated 1-6 ismaintained in position on the plate of the diagrammatically illustratedmovement 17 by four screws 18 disposed at with respect to one anotherand adapted to be screwed in studs 19 fixed to the plate and bearingradially against the ring. The balance wheel also consists of a. bipolarmagnet, here designated 2-0, which rotates within the ring, in the planeof the latter. By screwing or unscrewing the screws 18 to a variableextent, it is possible to produce in all directions an eccentricitybetween the ring 16 and the magnet 20, which eccentricity is ofadjustable value. This eccentricity and its direction create by magneticmeans an anisochronism ot' the oscillating member, whereby it ispossible, as in the first constructional form, to compensate for theanisochronism of the adjusting system of the timepiece.

The invention is not limited to the constructional forms described andillustrated. Thus, the oscillating magnet nee-d not itself constitutethe regulating balance wheel, but may be distinct therefrom. The magnetand the balance wheel will then be rotatable withone another.

What I claim is:

1. In a timepiece having an electromagnetically maintained regulator ofthe oscillatory type inherently prone to anisochronism, which regulatorcom-prises an oscillatory permanent field magnet, and a ring of materialof high magnetic permeability forming air gaps with the poles of themagnet and so forming flux paths with said magnet as to divide the fluxof the magnet into a number of partial fluxes equal to the number ofpoles of the magnet, the feature that said ring and the oscillatorymagnet are disposed slightly eccentrically in relation to each other soas to produce magnetically as the result of the eccentricity andoscillation of said magnet, anisochronism in the regulator at leastpartially compensating for the anisochronism to which the regulator isinherently prone.

2. In a timepiece having an electromagnetically maintained regulator ofthe oscillatory type inherently prone to anisochronism, which regulator.comprises an oscillatory permanent field magnet, and a ring of materialof high magnetic permeability forming air gaps with the poles or" themagnet and so forming flux paths with sai magne as to divide the flux ofthe magnet into a number of partial fluxes equal to the number of polesof the magnet, the feature that said ring has a radial air gap betweenadjacent ends thereof and is so disposed in forming the airgap as tointroduce eccentricity between itself and the oscillatory magnet for themagnet and ring to produce magnetically as the result of theeccentricity and oscillation of said magnet, anisochronism in theregulator at least partially compensating for the anisochronism toywhichthe regulator is inherently prone.

3. In a timepiece having an elcctromagne-tically maintained regulator ofthe oscillatory type inherently prone to anisochronism, which regulatorcomprises an oscillatory permanent field magnet, and a ring of materialof high magnetic permeability forming air gaps with the poles of themagnet and so forming flux paths with said magnet as to divide the fluxof the magnet into a number of partial fluxes equal to the number ofpoles of the magnet, the feature that said ring has a radial air gapbetween adjacent ends thereof, and said regulator includes adjustingmeans engaging said adjacent ends of the ring for the positions occupiedby said ends relative to each other to be altered to produce slighteccentricity between said ring and the oscillatory magnet and for saidring and magnet to create magnetically as the result of the eccentricityand oscillation of said magnet, anisochronism in the regulator at leastpartially compensating for the aniso- "chroni-sm to which the regulatoris inherently prone.

4.-ln a timepiece having an eleotromagnetically maintained regulator ofthe oscillatory type inherently prone to anisochronism, which regulatorcomprises an oscillatory permanent field magnet and a ring of materialof high magnetic permeability forming air gaps with the poles of themagnet and so forming flux paths with said magnet as to divide the fluxof the magnet into a number of partial fluxes equal to the number ofpoles of the magnet. the feature that said ring has a radial air gapanisochronism in the regulator at least partially compensating for theanisochronism to which the regulator is inherently prone.

5. in a timepiece having an electromagnetically maintained regulator ofthe oscillatory type inherently prone to anisochronism, which regulatorcomprises an oscillatory permanent field magnet, and a ring of materialof high magnetic permeability forming air gaps with the poles of themagnet and so forming'fiux paths with said magnet as to divide the fluxof the magnet into a number of partial fluxes equal to the number ofpoles ofthe magnet, the feature that said ring has a radial air gapbetween adjacent ends thereof, said regulator includes a rotata-blychronism in the regulator at least partially compensating for theanisochronism to which the regulator is inherently A,

prone.

6. In a timepiece having an electromagnetically maintained regulator ofthe oscillatory type inherently prone to anisochronism, which regulatorcomprises an oscillatory permanent field magnet, and a ring of materialof high magnetic permeability forming air gaps with the poles of themagnet and so forming flux paths with said magnet as to divide the fluxof the magnet into a number of partial fluxes equal to the number ofpoles of the contact with the circumference of the ring fordisplacingthe ringin the plane of the ring to produce slight eccen tricity betweensaid ring and the oscillatory magnet and bit for said ring and magnet tocreate magnetically as'the result of the eccentricity and oscillation ofsaid magnet, anisochrom'smdn the regulator at least partiallycompensating for the anisochronism to which the regulator is inherentlyprone.

References Cited in the file of this patent UNITED STATES PATENTS2,941,417 Junghans et al. June 21, 1960 2,945,940 Beyner et al. July 26,1960 FOREIGN PATENTS 7 569,483 Canada Jan. 27, 1959

